During the establishment of an optical connection in a network, the source node computes a path through the network and sets up the path by using a signaling protocol and a routing protocol. The optical connection may be, for example, a Sub Network Connection (SNC), which is a collection of one or more SONET (Synchronous Optical Network)) paths or SDH (Synchronous Digital Hierarchy) paths, and a suitable signaling and routing protocol may be, for example, the Optical Signaling & Routing Protocol (OSRP) that is used in a SONET system. The SONET standard is used in the United States and Canada and is a variation of the SDH standard. SDH is the ITU-TSS (International Telecommunications Union-Telecommunications Standards Sector) international standard transmitting information over optical fiber.
More particularly, an SNC is a connection from a node in a separately identifiable part of a larger network to another node in the network, and typically spans multiple nodes and links. As part of an SNC creation, switching paths are created along the nodes that are traverse by SNC, thus enabling data to flow from the originating node to the destination node. In other words, an optical network can be partitioned into a set of optical sub-networks interconnected by optical links, and the SNC is a connection across an optical sub-network.
When two SNCs, each originating in opposite directions, are being established at the same time and are contending for the same resource in the network, the condition known as “glare” may occur. Glare prevents establishment of SNCs between two nodes. Glare occurs because each node on either side of the optical connection are making a decision, independent of the opposite node, as to which line and “timeslot” to use for an SNC. Timeslots are the discrete quanta of bandwidth on a line. In other words, glare occurs because the bandwidth limitation on the line prevents the two SNCs from concurrently being established during the SNC set up phase between the two nodes. As a result of the glare occurrence, both SNCs are not established between the two nodes, even if there is sufficient bandwidth to establish at least one of the SNCs between the two nodes.
Therefore, the current technology is limited in its capabilities and suffers from at least the above constraints and deficiencies.